flutter-text-scaling-accessibility

name	flutter-text-scaling-accessibility
description	Test, review, or implement Flutter interfaces for large and platform-driven text scaling, including nonlinear TextScaler behavior. Use when Flutter work involves accessibility font sizes, text overflow or clipping, large-text layout support, or claims about Android or iOS text-size settings.

Flutter Text Scaling Accessibility

Make Flutter interfaces remain understandable and operable under the text-size settings they claim to support. Keep synthetic widget-test coverage distinct from evidence about real platform behavior.

Keep the scope precise

• Use this skill for Flutter text scaling and the layout behavior it affects.
• Use broader Flutter accessibility guidance for semantics, focus, contrast, screen readers, and target sizes.
• Preserve the project's declared platform and accessibility support. Do not invent a universal numeric scale requirement.

Model scaling faithfully

• Prefer Flutter's current TextScaler and MediaQuery.textScalerOf(context) APIs when production behavior depends on the platform scaler.
• Treat a numeric value such as TextScaler.linear(2) as a synthetic test input unless the test harness replays the target platform's actual scaler.
• Do not equate an Android or iOS text-size category with a fixed numeric multiplier without verifying the current platform and Flutter mapping from authoritative sources.
• Account for nonlinear scaling and font-dependent metrics. A single multiplier can produce different effective sizes across text styles and platforms.
• Avoid fixed-height text containers, avoid scaling text down merely to prevent overflow, and preserve reflow, reading order, and access to actions.

Build useful automated coverage

• Exercise representative small, medium, and large text styles through the same layout path used in production.
• Cover wrapping, truncation, scrolling, flexible constraints, translated copy, and actions adjacent to text.
• Prefer behavioral assertions about visibility and operability over screenshot-only evidence.
• When using a synthetic scaler, state what it proves and what platform behavior it does not reproduce.
• Keep automated coverage separate from a claim that an OS accessibility setting or category is supported.

Validate platform behavior

• Verify the maximum text-size setting within the declared support boundary through the operating system settings on a supported device.
• Use an emulator or simulator as platform evidence only when it faithfully reproduces the relevant scaler and font metrics; otherwise verify on real hardware.
• Recheck platform-category mappings against current official documentation when support claims, regression tests, or acceptance criteria depend on them.
• Test the complete task at large text, not only isolated text rendering. Confirm that content remains perceivable and controls remain reachable and operable.

Authoritative references

• Flutter accessibility UI design and large-font guidance
• Flutter migration guidance for nonlinear Android text scaling
• Flutter migration from textScaleFactor to TextScaler